Thanks Karl … guess he remains a silent star performer in rose breeding in my books
I find study quite interesting indeed.
I have a couple of seedlings from a cross between R. rugosa Alba Group and ‘Mutabilis’ that flowered for the first time in 2020 (the cross was performed in 2017) with an extended bloom time (at least 4/21 to 6/31), but the extension seemed to be due more to protracted flowering from long laterals produced progressively lower on the previous season’s growth than it was from any sort of true repeat bloom. I don’t know if anything can really be concluded from a first season of bloom, though, and I’m hoping to watch them to see how they change over time (if they change).
Stefan
Interesting Stefan!
Did you use mutabilis as a pollen parent?
So alba x mutablis, expected pentaploid and then rugosa x mutabilis expected diploid?
I have tried to use mutabilis last year as a sees parent with rugosa but none of these crosses take. Only a few seeds between mutabilis x palustris. Hope some will germinate!
Sorry, I meant to indicate that I used the white-petaled, single-flowered R. rugosa (R. rugosa Alba Group, not R. x alba), as seed parent; ‘Mutabilis’ was the pollen parent. I generally find China and tea varieties much more difficult to germinate than R. rugosa, which also produces significantly more seeds per hip, and accepts pollen from a huge variety of other species and hybrids. Even so, I had a fairly low germination percentage because of seed predation by Megastigmus. It wasn’t a very serious cross, really more of an experiment, but I was happy to see that the seedlings have produced rather nice flowers.
Your ‘Mutabilis’ x R. palustris cross sounds very interesting, and I also hope you’ll get some seedlings from it! R. palustris is a pretty variable species, from what I’ve seen; a form from Florida that I grow hardly even resembles forms from farther north, although maybe there is more taxonomic work that needs to be done. I’ve always thought that the cultivar ‘Scandens’ looks like a hybrid between R. palustris and R. chinensis.
Stefan
I came across an interesting addition to the subject:
Theor Appl Genet 119:767-781 (2009)
A survey of flowering genes reveals the role of gibberellins in floral control in rose
Arnaud Remay, David Lalanne, Tatiana Thouroude, Fabien Le Couviour, Laurence Hibrand-Saint Oyant, Fabrice Foucher
http://bulbnrose.x10.mx/Roses/breeding/RemayGibbsRoses2009.html
Interestingly, three genes, i.e. RoVIP3, RoSPY and RoDELLA, were found in the vicinity of two important loci: a QTL governing the flowering date (or precocity) and the RECURRENT BLOOMING locus. No recombination was found between RB and RoSPY when 91 individuals were analysed. These genetic data indicate a possible role of GA signalling in flowering control in rose (flowering precocity and recurrent blooming).
So, rebloom and precocious bloom are not the same thing. And it should be possible to select for precocity (blooming at an earlier age) within a species before crossing it with rebloomers.
I can’t find the paper and I am sure you have already found it 4 yrs later. Rebloom in Rosa rugosa is a point mutation to a G in the homologous gene.
Please feel free to correct me.
In my climate it’s all Casiorhodon and forget Chinensis. For rebloom I also use Rosa beggeriana. Lovely rose.